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sediment core Articles

When assigning site-specific restoration targets for deteriorating aquatic systems, it is necessary to have an understanding of the undisturbed or background state of the system. However, the site-specific characteristics of aquatic systems prior to disturbance are mostly unknown, due to the lack of historical water and sediment quality data. This study aims to introduce a method for filling ...

A diffusive gradient in thin films (DGT) is an in situ sampling technique for the quantitative analysis of contaminant concentrations that is based on the diffusion and adsorption of contaminants onto resin gels. In the current study, a DGT technique was applied to measure total mercury (Hg) and monomethylmercury (MMHg) concentrations in lake and coastal sediment pore waters and to compare ...

Site soil conditions frequently limit the selection of a treatment process. Process-limiting characteristics such as pH or moisture content may sometimes be adjusted. In other cases, a treatment technology may be eliminated based upon the soil classification (e.g., particle-size distribution) or other soil characteristics. Soils are inherently variable in their physical and chemical ...

The aim of this work was to study the accumulation and fractionation of P in the inlet and outlet sediment of a constructed wetland for the wastewater treatment of a metallurgic plant in Argentina. It was important to predict whether P could be released into the water again by changing environmental conditions or retained over time. P-fractionation was performed using a sequential extraction ...

In the mid-1930s, the first string-wound depth filter cartridge entered the U.S. market. It was made from a woven wire mesh core surrounded by a cotton yarn, which was wound to form the depth filtration medium. The yarn itself was a tightly twisted medium and the major filtration essentially took place at the points of crossings of the yarns- which formed a diamond-shaped pat-tern-rather than ...

Polybrominated diphenyl ethers (PBDEs) are flame retardants used in a myriad of applications and are monitored worldwide because of health concerns. In this application, PBDE congeners were extracted from two sediment samples (certified sample and sediment core from Lake Maggiore) according to EPA method 3545A using the SpeedExtractor E-914 and determined by GC-MS/GC-ECD. The results were ...

Triclosan (5‐chloro‐2‐[2,4‐dichlorophenoxy]phenol) is a relatively new, commonly used antimicrobial compound found in many personal care products. Triclosan is toxic to marine organisms at the micrograms per liter level, can photodegrade to a dioxin, can accumulate in humans, and has been found to be stable in marine sediments for over 30 years. To determine the effects of triclosan on marine ...

Total atmospheric contribution of mercury (HgT) to lake sediment was estimated using 210Pb-dated sediment cores. Algorithms based on estimates of lake and watershed processes were applied to more accurately assess anthropogenic contributions of Hg to the environment and HgT. Factors addressed include: lake-specific background accumulation rates of Hg (HgB), variability of sediment accumulation ...

The contamination of surface waters through human activities has been increased over the past years as population density has increased. To fully understand the anthropogenic impact on an ecosystem, long-term data from chemical, physical and biological indicators are needed. To many people, heavy metal pollution is a problem associated with areas of intensive industry. Metals, such as nickel and ...

A shoreline revetment and sediment capping project along the Collins Cove coast of Beverly, Massachusetts required an erosion solution. The Challenge: Trying to maintain a system that will prevent loss of soils in a dynamic coastal environment is always challenging. As in most erosion control applications the revetment is intended to protect the underlying geotextile. In this particular ...

In the July 2002 issue dedicated to environmental dredging of World Dredging Mining & Construction, DEC present its newly developed in-situ immobilisation and capping technique for polluted sediments, the 3SI-technique. DEME Environmental Contractors N.V. (DEC), a Belgium-based company specialising in remediation and recycling or disposal of water bottom sediments, is offering a vast range ...

Two piston cores, collected from the western Ulleung Basin of the East/Japan Sea, were used to investigate the Late Quaternary tephrostratigraphy, lithology, and mineralogy of the sediments, as well as the elemental composition of both sediments and interstitial water, and their paleo-environmental implications. The cores show two lapilli tephra layers and one rhyolitic ash layer at the ...

Nine surface sediments and a dated sediment core collected from urban lakes in Wuhan, Central China, were analyzed to investigate the concentrations, occurrence, composition, and depositional fluxes of polychlorinated biphenyls (PCBs). The concentrations of {Sigma}PCB (the sum of 39 congeners) in surface sediments ranged from 0.90 to 46.14 ng g–1 dry weight. Only in Longyang Lake and Nantaizi ...

Organic-rich sediment samples collected from a transect within, and below, the Oman Margin oxygen minimum zone (OMZ) were analysed using a sequential leaching technique to characterise the diagenetic behaviour and speciation of Mn and Fe in operationally defined sediment host fractions. Trace metals showed distinct diagenetic behaviour in the two contrasting environments that were sampled. The ...

Project: McCormick & Baxter Superfund Site Location: Portland, OR Products: Organoclay Reactive Core Mat Background: The former McCormick and Baxter Creosoting Company is located in Portland, Oregon on the Willamette River. This Superfund Site encompasses approximately 41 acres of land and an additional 23 acres of ...

Endocrine-disrupting chemicals with estrogenic activity (e.g., alkylphenols) have been detected in coastal Japan. We aimed to determine estrogenic activity in extracts of river water, seawater, sediments, and sediment cores from Tokyo Bay by in vitro gene expression assay. Fifty-one of 57 extracts had some estrogenic activity. E2 equivalents (ng E2 equivalents per gram dry weight or per liter ...

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